Screw-making machine.



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scm-:w MAKING MACHINE.

(A pplicatiol; led Jan. 20, 1902.)

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(Application led Jan.: 20, 1902.)

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No. 7|2,5o6.

F. CURTIS'.

SCREW MAKING MACHINE.

(Application mea Jan. 2o. 1o2i) 6 Sheets-Sheet 3.

(No Model.)

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Rms Prrzns co. PHoTuLm-la, wAsmN Patented Nov. 4, |902.

cunTls. SCREW MAKING MACHINE.

(Appncgeion med .my s, 1902.) 6 Sheets-*Sheet 4.

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No. 7|2,5o6. Patented Nov. 4, |902.

F. cunTls. SCREW MAKING MACHINE.

(Applica'on filed Jan. 20,. 1902.)

6 Sheets-Sheet 5.

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(No Model.)

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6 Sheena-Sheet Making Machines; and my preferred manner `a series of screws which are complete except -on the line 3 3 of Fig.` I.

V is an enlarged front elevation of the deadspindles and guide,partly in section, and the cam for moving the dead or tool spindles and `the stop. Fig. VI is asection on the lineG 6V FRANK CURTIS, CF "INGERSOLL, CANADA.

sor-u-:w-MAKiNcMAcI-HNE.`

sPEenrcATIoN forming part of Letters Patent No. 712,506, dated Nvember 4, 1962.

To all whom it may concern.-

Be it known that I, FRANK CURTIS, a citizen of the United States, and a resident of Ingersoll, Oxford county, Province of Ontario, Dominion of Canada, have invented cer-1 tain new and useful Improvements in Screwof carrying out the invention is set forth in: the following ful,clear,and exact description;` terminating with claims particularly specifying the novelty.

This invention relates 'to metal working machines, and more especially to those designed for making screws; and the object o'f the same is to produce a machine which shall be entirely automatic in its operation and of such construction as to turn out very rapidly for the finishing-that is to say, the contour of the bar of. stock used constitutes the shapei of the head, and my machine turns the reduced body thereof and cuts the thread thereon, and with this machine it is understood that there are to beemployed devices for automatically cutting or severing each finished. screw from the stock-bar before the latter is. ready for the next operation, and it`` is also to be understood thatthe finished screws mayy thereafter be polished or treated in any de-l 'sired manner before they are boxed for shipnient.

To this end the present invention consists in the construction of a machine of this character on substantially the lines hereinafter more fully set forth, by which is produced; mechanism-proven by actual experimentztoz have turned out a materially larger number of screws in a given time than any machine; now on the market.

In the accompanying drawings, Figure I is: a front elevationof this machine complete. Fig. II `is a-scction onthe line 2 2 of Fig. I,i giving an end view of the live-spindle head removed from Athe base. Fig. III isa section e Fig. IV is a longi-` tudinal section of the live-spindle head and an elevation of the friction-clutch and the mechanism connecting these two parts. Fig.

Application filed `l'anuary 20, 1902. VSerial No. 90,428a (No model.)

ofFig. V. Fig. VII is a detail of the connector between the tool-spindles and the stop. Fig. VIII is an enlarged rear elevation, partly in section, ofthe die-spindles and guide and the mechanism for operating them. Figs. IX and X are sections on the lines l) 9 and 10 10 of Fig. VIII. Fig. XI is au enlarged detail of a safety device to be described hereinafter. Fig. XII is an enlarged longitudinal section of the friction-clutch. Fig. XIII is a crosssccti'on on the line 13 13 of Fig. XII.

Referring to the said drawings, the numerals l designate the base of this machine,which supports the superstructure, and in this base isjournaleda cam-shaft 2. The cam-shaft 2 is driven by power,which in the present iustance is a belt 3, leading froma suitable source, although, of course, it might be gearing. By preference I interpose between the power-wheel 4 and the shaft 2 a safety device,

(best seen at the right of Fig.` 1,) which is of the following construction. Said powerwheel here drives a worm 5, which engages a worin-wheel G, mounted loosely on the shaft 2 between fixed collars4 7, and through one of said collars are threaded screws S, directed toward the worm-wheell. The purpose of this construction is to permit said wormwheel, which is driven with great force by the worm, to slip between the-collars and therefore to turn upon the cam-shaft 2 at `times when through any interruption or acci- `dent the -rotation of the cam-shaft may be temporarily checked or retarded, and hence this safety device prevents the breakage of `the machinery or its product if thescrews 8 are set to the desired tension. It will be well understood, however, that I reserve the privilege of employing a safety device of any other equivalent construction or of omitting the safety device altogether, if preferred.

Upon the base'is supported the bed l0,which in turn carries the various parts of the machine described belowas the spindle-driving mechanism, thelive-spindle head, the spindle or tool guide, the die-spindle guide, and the die-spindle retractor. Upon the cam-shaftis mounted the friction-clutch and cam for intermittently turning the spindle-head, the

cam for operating the mechanism which locks and releases this head, and the two cams which m ove the various spindles and the stop.

These parts will Anowbe described, Working as far as possible from the'left end of Fig. I toward the right.

f' Referring more especially' to Figs. XII and XIII, I preferably employ a friction-clutch of the following construction for intermitsaid cone 19.

and mounted loosely on the hub 22 is a drivtently turning the spindle-head through the mechanism. shown in Fig. IV: Onthe camshaft 2 is fixedly mounted a cam l2, having a longitudinal cam-face 13 at one point, as shown herein. Pivoted, as at 14, within the bed 10 is a yokerl, carryinga plurality of rollers 16 and 17, the former being so disposed within the yoke as to be struck by the caml'ace 13, while the rollers 17 are so disposed as `to project to the'other side of the yoke and bear against a collar 18, which is mounted loosely on the shaft 2 and has a cone-face 19. 2O is a key or any equivalent device by which there is fastened to the shaft a collar 2l, having a hub 22, around which is screwed va band 23, which is adjustable. 24 is a second collar, mounted movably upon said hub 22 and having a slotted hub 25, in whose slots are pivoted levers 26, each having an angularlydisposed nose 27, bearing against said band 23, While its outer vrounded end rests upon Between the collars 2l and 24 ing-gear 30, meshing with a smaller gear 3l. on a counter-shaft 32, mounted in bearings in the bed 10, and this counter-shaft carries a largergear 33, which extends upward through the case 35 of the live-spindle head 34 and` engages teeth 35 thereon. Such head turns Within the case, as best seen in Fig. IV, and in the present machine it is constructed like a spool in whose ends are fixed boxes 37, in which are mounted live-spindles 38, each having a chuck 39, as usual. Power applied through b elting or gearing to the wheel 40 drives the gear 4l, which meshes with the outer series of teeth on a rim-gear- 42, (see Figs. IIvand IV,) and the inner teeth 0n this rim mesh with a series ot' gears 43, eachof which is fast on a spindle 38. Thus when the power-wheel 40 rotates the various spindles rotate within their boxes 37, and this movement is independent of the turning of the head 34 within the case. 44 designates collars between the gears 43 and the boxes 37 at the outer end ot' the live-spindle head. The rim-wheel 42preferably has a fiange 45 turning around the end of the casing 35, as indicated in Fig. IV.

In Fig. III s best seen the mechanism for locking and releasing the head 34 within the casing or shell 35. designates recesses located all in a single plane through one end of said head, there being as many recessesras there are spindles. Within a chamber 5l-at Vone side of the casing 35 is located a latch 52, vpressed normally forwardly by a spring 53,@

whose tension is adjustable by a screw 54,5 and when a recess 50 is brought into registerA with the line of this latch its Yspring throws.

.its inclined or beveled tip thereinto, so as to` Iprevent further turning of the head within thecase. In connection with the latch I have shown and I preferably employ a tightening device consisting of a Wedge 55, resting on the inclined bottom 56 ofthe chamber 51, and a screw 57 for adjusting this wedge to take up Wear of the latch; but this tightening device might be yomitted or could be replaced by other equivalent mechanism. In said Fig. III, I have shown at the opposite side a similar chamber 61, with all similar parts therein, which I have numbered to correspond with those used in the paragraph above. Thev tip of this latch is inclined in the opposite direc-v tion, though it engages the same series of recesses 50, and it follows that its function is to prevent a retrograde movement Within the head or shell 35. This retaining-latch may or may not be used, as desired, and by experiment I have found that it is not absolutely necessary, especially if all the cutting mechanism operating on the work in this machine has a tendency to turn the head in the direction of the arrow in this View.

Mounted on the cam-shaft 2 is a cam 70.,

jection 71 at one ppint, and in the rotationof this disk this face passes under one end of a trigger 72, suitably pivoted and supported, as at 73. The other` end 74 of this trigger enters an opening 75 in the bottom of the chamber 51, passing through a similar opening 76 in the wedge (if the latter is employed) and extends into an opening 77 in the latch V5.2, and the movement of the trigger retracts the latch, so as to permit the turning of the head at the proper times.

Mounted in standards 80, rising from the bed l0, are the dead or tool spindles, and in the present instance I have shown two of them, (numbered 8l and 82,) while there is a third member,(num bered 83,) which is used as a stop, as described below. It will be understood that there may be a greater or less number of spindles and that the stop is not neces'- sarily of this construction. By preference a screw 84 enters the rear end ol' each of these members and is squared or made angular, as at 85, or otherwise shaped at its outer end to permit its adjustment -within the spindle. On this screw is formed a fixed shoulder. 86, and outside of the same is a jam-nut 87. 88 (see Fig. VII) is a connector having holes 89 spaced to receive these various screws 84,Y

and it is clear that the several nuts 87 may be loosened to permit the turning of the screws and then tightened to clamp the connector between them andthe'shoulders 86.

The spindles pass through collars 90, mounted Within the t'ront standards 80, as best seen in Figs. V and VI, and are splined within said collars, las at 91, so as to prevent the rotation of these dead-spindles, but permit their longitudinal adjustment when adjusted by the screws 84, above described. In order'to permit the rotary adjustment of anyspindle IOO IIO

when desired, Imounteach'collarQO loosely within the standard and" employ a setscrew 92, preferablypointedat its inner end, to takel into `notches 93 in the collar. 94 designates tool-holders,whichare mounted upon the inner ends of the spindlesSl and82, being pref-1 erably screwed thereon; The mechanismfor moving vthese dead -spindles longitudinally* consists of` a cam 100, fasti upon thesha'ft 2v and having a cam-groove 101 of'propershape. Within the latter travels a roller or pin 102y at the lower end of a lever 103, which is piv voted, as at 104,to the bed 10, and the upper endofthis lever is couneetedwithone ofthel dead or tool spindles in any suitable way? In .l the` presentlinstance I have shown saidV upper end' ofthe lever `pivoted, as atrl0,tot a block-i106, whih surrounds the spindle 82j l and is rendered` adjustable thereon by. means of a set-screw 107, although it will be clear l that other-formsrof connection could be em"` t ployed. .o B ymeans of the connector S8, above .describedpwhen the spindle 82 is movedrlongitudinallyby the camand lever the other: spindle orl spindles and thestop` S3 areV movedj with it, yet eachiscapable of individual lon-j gitudinal adjustment; and each spindle is ca zpableof rotaryfadjnstment by means of the:

collar 90. l u. c

110 is a cam` or wheel fast `on the shaft 2.

and `having aLcam-face 1110n its periphery;

properlylocated-and shaped to strike a roller? er1` other projection 112 on the lower end `of al lever113,lwhi`ch ispivoted at 114.tothe bedl 10.` The upperend of` this' lever is jloosely-` pivoted at'1l5 to'a fork 11.6,1which slides lon-; gitudinallyon a guideTrod 117,` fixedly` 'm cunt-.1

'ed in two standards 118 and extending beyond t the forward or Ainner standard, where it isprovided-.with two grooves 119., as indicated inl dotted-lines in 1Fig.VII`I, and tfhe lever? 113,?

.stummen une forkns held againstthe tendoncy of saidcamlface in the-presentinstance1` by a springl`20, although this could loeavoid-y edby a different-shapenof cam-face.V l

Mounted forlongitudinal and rotary movements `in thetwo standards 118are' the die-1 spindlesfl21, `two being shown in the present instance and each having agdieholder 122fat its forward or inner end. @Each spindle, nearl `itsinnerend;ismounted loosely within a long sleeve"123,`V whichextends through the standardf118 and -hasan` integralfhead 124 `at its innerend, this head having Aa pin 125, which` moves in' one ofthe grooves 119.in the guide-1 rod-117.- Upon the other end of this sleeve ismounted `a collar 126, and from eachcollar projectsrigidly a hook -127,wh'ose tip enters` loosely intothe groove offa clutclt member 128, `which is splined, as at129, yonthe ispindie; The arms ofpthe. fork 1 1116` above-inem' ,111 andthe `spring 120.111 l L tioned also enter the `groove offthese elulehl members, whereby the'latten are moved `toI and fro under theimpulse ofwthe cam-fac -`l` he die-spindlefrotating mechanism` conl sof a' power-gearlSO;driveirbybelting;orl

.gearing `and fixed en, a. shan i131, whiehfis gears 134,1nou nted loosely on reduced portions t 135` of:` the spindles 121,-as bestseen; in Fig. `VIILand said gears134 have pins136,.adapt `bers 128, as will be understood. Said reduced portion 135 ofreach spindle, after passing through -the gear134, has -a collarf138` .fixed thereon and .permitting slight longitudinal movement iwithin a `c`avity..139 `in-'the rear .standard 118;` Continuingthrough said standf `ard; the'reduced portion of the spindle is snrrounded by a spring 140,eXerting expansive force between said standard and a collar 141 ratthe extreme'end of the-spindleandfhavr `ing a tendency tohold thelatter normally inl` its outermost position.

`121of the spindle fromits reduced portion ber, which is the driven gear 134, andpresses `the latter normally toward the rearstaliflard 118, ,while if the spindle is moved fi ard `the collar-138 will obviously cause lthe-gear A134E to movewith itnand thehlength ofthe driving or drum gear 133 will prevent the'ces- Asation ofrotationn In the adjacent'faces of .theholders`122 and the sleeve-heads 1211` are seenin Fig. -VlIL and as one' member -is .revolubleand the other isnotthese pins located therein produce a' clutch. r i i 145 `designates stops adg set-screws-lfl in the inner standard 118'and all for a'purpose to be hereinafter described.`

`which is by preference screwed-into each col-- the adjacenti'clutch `memberi128,and `within a spring150,which isofi greater. power-than it may be operated` successfully there-is a -`triflinglost motion between the-ti p of thehook "member 12S; i `With the above construction lof.. parts -f the? `operation of rmy machinevis `as followsythe "to perform their functions in correct relations to each 4other and power=being`applied at14,

40,'and 130, as above indicated: :Barsof iron, forming .the stock-lifroinwhich theiscrewsare will; hethe lengthiof` the f1nislied.'serewr` "It xjournaled finlstandards 1132." This shaft car-` `ries a drum-gearl133, `which engages driven.

ed to engage other` pins `137on the clutch mem- This tendency hold the shoulder 11L2,\which` separates the'bodv 135,normall y against the toothedyclutch meme pins `143,-having inclined engaging faces, -as

ustablel underhthe t Referring now to Fig. Xl,148isa pocket,`

lar` 126 and opens through the. same toward.

the'spring 140, the purpose of this stop `being `also.hereinafterexplained, and'in order that l having their innerendsll' :npturned or shaped so as to bestruckrbythe .collars.126,

IIO

this pocket is astop149, pressed outward by 127` and the walls of the groove insaid clutch :T20 `partsbe'ing properly shaped and timedso` as' `to be made, `are. ins'ertedfrom` the `left inFig.` i I one fat la time through` thenemptyfspindle 38 as itis movedtby the turning of eithe. head r '34 to -the lowerinost=position,andeachvbar is `then pushed inward until its innemend strikes the stop 33, whiehr permits the' ibarto project' `beyond the ch nek 349 'forlj ust adistaiicew'hich is "understoodthatfthe `contour `ol;` this bar is 50 on the other side.

5 head from the stock remaining, and it is also to be understood that the stock-bar is loos-` ened and tightened in the chuck 39 on the lowermost spindle either by hand or by mech-V anism forming no part of the present invenio tion, and' therefore not illustrated and described herein. I have also not 'shown the roughing-tool, which is mounted in the lower- Y,most tool-holder 94, nor the finishing-tool,

which is mounted in the uppermost tool- 15 holder 94.` These turn out the body of the screw. Nor have I shown the first and sec- Vond dies, which are mounted, respectively, in

l the upper and lower die-holders 122 and cut` "Whe thread upon said body; but it will be lhear that as the blank progresses. under the turning of the head in the direction of the arrow in Fig. III the stock will move upward from the lowermost position in Fig.'I and be opsated upon in turn by the roughing-tool, then the finishing-tool, and then it will pass over the top and downward at the rear, so as to be operated upon by the upper or first die and'finally the lower or second die of Fig. VIII, after which the finished screw is severed and the spindle reaches the bottom position again, where the stock is fed forward for a new operation. The cam is so set upon the shaft 2 that its face 7l is properly timed to act on the trigger 72 and retract the latch 52 'just before the cam-face 13 acts on the roller 16 and swings the yoke l5. The latter movement presses the cone 19 between the rounded ends 28 of the levers 26 and` causes them, through their pivotal connections with the hub 25, to move the collar 24 toward the collar 21. The driving-gear 30 is thus'temporarily clamped between these collars and turned for a partial revolution with the shaft 2, and through the intermediate gearing 31 and 33 it imparts a partial rota` tion to the head 3i, which by the length -of the cam-face 13 is just sufficient to turn the head a distance which in the present instance is one-fifth of a revolution. However, in order to be certain that the distance turned is the proper one, at the moment the spindle containing the then shortest bar of stock reaches the lowermost position the latch 52 engages a recess 50, and the retaining-latch 62 (if it is employed) engages another recess It will be understood that while the empty lowermost spindle is being filled or the stock therein fed forward against thestop the tools and dies are performing their work on the other material, and also that the new stock is not supplied or fed forward until the finished screw has been cut off. In order to have this work performed, the spindle -driving mechanism above described is rotating the five spindles at the required speed, but the fact that it rotates the spindle through which the' new stock is being fed is not detrimental to Ithe successful operation of mymachine.

The cam 100 is of such size and its groove 101 so shaped that after the nished screw has been severed at the rear of the machine Vand the mechanism above described has turned the head 3l to bring the stock from which the screw was cut to the lowermost position the feed of the stock commences and the cam, through the lever 103, simultaneously moves forward the three spindles shown vin Fig. V. During this forward movement the roughing-tool operates on the stock which has last been fed forward, and the finishingtool operates on the material which has last been roughened, and Ijust at the moment when these two tools have finished their work the stop strikes the projected extremity of the new piece of stock and the feed of the latter terminates, while the groove in the cam 100 has done its complete work and the retraction of the three spindles now commences. It is quite obvious that the cam-groove may be so shaped as to cause this retraction to be more speedy than the forward movement. When these members have resumed their original position, the head 34 is turned forward one additional step, which obviously carries the first piece of material whose turning is finished over to the rear of the machine ready to be treated by the first die and necessarily moves the roughened piece of material up into position for operation by the finishing-tool.

Having explained the manner of operating the head 34E, of feeding the stock, and of roughing and finishing the body of the screw being made, it remains only to cut the thread thereon, and this is accomplished by dies of the usual construction, which are mounted in the holders 122 and operated by mechanism best seen in Fig. VIII. I t is to be understood that as the finished material passes over the top of the machine it is operated on first by the upper or first die, which produces a partial thread, and then by the lower or second die, which finishes this thread, although it is clear that the screw might b e finished by one die, as it is not necessary in all cases to have both dies. the position shown in Fig. VIII, as the cam 111 strikes the roller 112 the lever 113 moves the fork 116 to the right and with it moves the two clutch members 12S, which are splined on the spindles 121. The lost motion' of the tips of the hooks 127 within the grooves of these members permits the latter to strike the collars 126, which, with the sleeves 123, are also vmoved to the right, their heads 124: being prevented from rotation by the pins 125 and grooves 119. As soon as the pins 143 on these heads and on the adjacent faces of the die-holders 122 engage, the spindles commence to move forward, though without rotation, and when the mouths of the dies engage the extremities of the rotating pieces of stock the turning of the latter tends to more tightly en- IOO IIO

IIS

Beginning with the parts in sleeves 123, collars `126, fork`116, and clutch gage the inclinedfaces of the pins 143. AJust at this time the roller 112 passes the cam 111,4

.and the spring would return the `parts to` the position shpwltif it` were not for theengagement` of `saidi'nclinedfaces of the pins `14:3. V 4Meanwhile the `collars 13SI have been retaining the fgears 134 inn position against theshoulders142, and these gears are rolated `constantly-in the same direction as the live! spindles, but with greater speed, by thef'shaft 131, which isdriveu by power from the pointll .130, ."The gears 134 have therefore `been 4moved along on, thedrum-gear 133, thoughi` `'they yet remain" in mesh therewith. l `The pitch of the thread Withinthe dies now draws` the latter farther forward,"andcliltchlpins` theidies, with'the holders and their spindles, .immediately begin to rotate with the screw.

The spring 120 now immediately returns the members 128 to the left until the, pins 137 en-` gage the pins 136 onthe rapidlyrotatinggears` 134, and the latter causes an accelerated ro-` i as ` sition shown in Fig. VIII.

tation of the spindles in the same direction, Whichdraws the dies off` the screws they have just made and returns the parts to the po- I have spokenof a certain loosenesswhich the tip of the hook 127has within the groove of the clutchmember128`and whichallows a Alittle lost motion in the longitudinal movement of these parts,;and thepurpose of this` lost motion willnow appear. In machinesr of this character thefirst die usually cuts only part of the depth `of the thread and the second dienishes it, and it is clear that unlessthe thread in the seconddie be startedj accurately within the partial thread `cut on; the stock by the first die the first or partial thread cut thereon will be ruined, this being known as crossing the threadf? In Fig. XI is shown one form of safety device which I employ for preventing this contingency. i Se-y cured to, as by being screwed into, the collar'` 126 of the second-die sleeve is a pocket 14:8, havinga spring-pressed stop 14:9, as described above, and when the clutch member 128 moves forward it makes a yielding contact with the collar 126 rather than a positive contact, as

may be made between the other clutch mem` ber and collar. The result is that theyieldJ ing of the stop permits themouth ofthe n` ishing-die and the threads therein to accommodate themselves to the threads which have been partially formed by the first die, and

y hence the threadsin the finishing-die adjust themselves properly tothe threads which haveV been made-on the stock by the iirstdie. I consider this an important feature of my in vention, and' experience; has proven that it saves a large percentage of waste; but 1t 1s ses 5 cleartthat` other furnis ofsafety device could be employed at this point, the essentiali'ea` ture being to .permit a slight yielding at the moment that the mouth ofthe finishing-die `emissies, the` up or rhestockwhicuhas aiready been provided with a partial thread.

During all of the above operation should anythiugoccur by accident or design which "checks or retards the proper ,operationofthe mechanisms Aconnected with and driven by the four cams on the cam-shaft 2 "the safety device shown at the rightend of` Fig. I will permit thisshaft to cease its rotation either temporarily `or for sufficient time to call attention to the abnormal condition; but I consider it` hardly necessary to employ` safety `devices at the point 140 and 130,`for` the double reason that power can `here be applied by belting, which always permitsfcertain slipping in cases of emergency, and also because the work performed by'these belts is not such as would ordinarily cause destruction of stock or machine. y y f I do not confine myself strictly tothe details of construction above described npr-te their use simultaneously ina single maehine, although byV practical experience I am con- `vinced that they work successfully together. Some collateral elements are not illustrated, as theyformno part of my inventionybut they have been referred to because theinuse is well known, if not necessary. VThe sizes, shapes,and proportions of` parts are not essentially those employed herein, andA thematerial used is preferably entirely metal except the belting. It is clear` that a greater or lesser number of spindles could be employed without departing from the spirit of myin# vention.

Having described my invention, what I `claim as new, and desire to secure by Letters Patent, is

1. In a screw-making machine, thefcombination with a plurality of live-spindles; of standards, dead-tool spindles movable therein, a stop also movable therein, a connector between the `spindles and stop, means for moving these members simultaneously, other l dead-spindles movable in Athe standardsfor carrying dies, and means for operating these spindles independently of the toolspindles- 2. In a machine of the character described,

the combination with a spindle-head having `for tripping this latch just before the turn` ing of the head commences, a latch-chamber `haviugan inclined bottom, and` a wedge `thereon beneath the latch, as and for the purpose set forth. a

. 3. In a machine of the character described, `the combination with a spindle-headha'ving a series of peripheralrecesses ina single IOO rio

plane, `spindles. located. in said head, .and `means forl turning the' head intermittently5` of a retaining-latch having a beveled tipi adapted to engage one of said recesses, an-

other latch whose tip is oppositely beveled` and adapted to engage -another of the same series of recesses, means for tripping this latch jnstbefore the turning'of the head commences, chambers forthe latches disposed at opposite sides of the'head and having in-l clined bottoms, and independent wedges on said bottoms .below the latches.

4. In a screw-making machine, t-he combination with the live-spindles; of two dieholding spindles, means for moving them backward and forward, a safety device interposed between one spindle and the means formoving it forward, and means for rotating both spindles in the direction in which the live-spindles rotate, but more rapidly, after the screw has been threaded,as and for the purpose set forth.

5. In a screw-making machine, the combination with the live-spindles, and means for roughing and finishing the stock so as to prodglce screw-bodies; of two die-holding spin- Vdiesbf which the first die forms a` partial threadmon-the screw-body just turned and the second. completes it, means for operating thse spindles, and a spring-pressed stop .interposed between said operating means and the finishing-spindle, as and for the purpose set forth.

6. In a screw-making machine, the combination with the head containing a plurality of live-spindles, and means for turning said headintermittently; of a series of dead-spindles carrying dies, a second series carrying tools, a stop connected with said second series whereby tools, dies, and stop standin alinement with the live-spindles, a single means for moving the die-spindles in one group, and independent means for moving the tool-spindles and stop in another group forward and backward, as and for the purpose set forth.

7. In a screw-making machine, the combil nation with a plurality of live-spindles; of standards,.dead-spindles movable therein, a stop also movable therein, a connector adjustably attached independently to the spindles and stop, and means for moving these members simultaneously.

8. In a screw-making machine, the combination with the live-spindles, the die-spindles, clutch members splined on the latter, a fork engaging said members, and means for moving the fork backward and forward; of mechanism for preventing the rotation of the die-spindles during their forward movement, other clutch members loose on these spindles and rotating constantly in the same direction as the live-spindles, and means for disengaging said mechanism which prevents ro-` tation and engaging said clutch members at the moment the thread on the screw is finished, as and for the purpose set forth.

9. In a screw-making machine, the combition with the live-spindles, the die-spindles,

clutch members splined on-thelatter, and

ingsaid drum,- means forcau'sing these gears to move longitudinally with the spindles, and pins in these gears and on said clutch members whereby the die-spindles are rotated in the same direction as but more rapidly than the live-spindles when said pins'are in engagement, as and for the purpose set forth.

10. Ina screw-making machine, the combination with'the live-spindles, the die-spindles, a sleeve surrounding each of the latter and having a head, clutch elements between this head and the d-ie-holder, and means for preventing the rotation of Asaid head; of another clutch whereof one member is splined on the spindle and the other is loose thereon and rotated constantly, means for moving the splined member backward and forward, and connections between this member and said sleeve. y

l1. In a screw-making machine, the combination with the live-spindles, the die-spindles, a sleeve surrounding each of the latter and having a head, clutch elements between this head and the die-holder, and means for preventing the. rotation of said head; of an ing said groove, as and forthe purpose set forth.

l2. In a screw-making machine, the combination with the live-spindles, the die-spindles, a sleeve surrounding each of the latter and having a head, clutch elements between this head and the die-holder, and means for preventing the rotation of said head; of an annularly-grooved member splined on the spindle, means for moving this member backward and forward, a collar fast on the sleeve adjacent this member, a hook on the collar engaging said groove and having a certain lost motion, and a yielding stop carried by the collar of the finishing-die spindle, as and for the purpose set forth.

13. In a screw-making machine, the combination with a, live-spindle, a die-spindle, a sleeve surrounding the latter and having a head, means for preventing rotation of this sleeve, and pins on the head and the dieholder forming clutch elements and having inclined engaging faces; of means for moving the sleeve forward, a stop for checking such movement at a predetermined point, and yielding means for drawing the spindle and sleevel in a direction opposed to the frictional pull of said clutch-pins.

14. In a screw-making machine, the combi- IOO IIO

asleevesurrounding each `of the 'latter and having ahead, means for preventingrotation of this` sleeve,` and pins on the head and the wdie-holderforming clntchelements `and having inclined engaging faees; of a collar on Said Sleeve, a stop for Apositively preventing forward movement of the sleeve,means` for moving the collar forward and backward, and yielding` meansvfor drawingr the spindle in a direction opposed to t-he frictional pullofsaid" clutch-pins.

, l5. In a screw-makingir machine, the combination with the live-spindles, the die-spindles,` a sleeve surrounding each of the latter and having a head, meansfor preventing rotation-` of this sleeve, and pinson the head and die; i holder forming clutch elements and havingA inclined en gaggingy faces; of a collar on said sleeve, va stop for positively preventing forward movement Vof the collar, a member splinedlon the `spindle adjacent to the collar,

the splinedlmembcr forward and backward, ,and yielding means for drawing the spindle in `a directionA opposed to the frictional pull of said clntchpins,as and for the purpose set forth..F i

Ia testimony whereof I have hereunto subscribed mysignature this 15th day of January, A..`D. 1902.

Witnesses:

N. L. COLLAMER, F. R. FITTON.

connections between these 'elements permite1 `tingzga certain lost mot-ion, as said splineii` member moves forward,means for moving;V

FRANK KCURTIS. i 

